- After I run a maximum likelihood estimation using fmincon, I got the following message:
Optimization terminated: magnitude of search direction less than 2*options.TolX
and maximum constraint violation is less than options.TolCon.
In the meanwhile, the first-order optimality is still a large number.
Is this a good termination? Shoudn’t the first-order optimality be close to zero?
- If the t value for some estimated parameters are very small, does that mean these parameters cannot be accurately estimated with data? The likelihood is very flat over these parameters?
I also noticed that the estimated value will not deviate a lot from the initial values for these parameters. Does that mean data do not have enough information to estimate these parameters?